Temperature changes in the root ecosystem affect plant functionality

Climate change is increasing the frequency of extreme heat events that aggravate its negative impact on plant development and agricultural yield. We show that to analyze the consequences of heat, we need to cultivate the plants with the root system in a temperature gradient. For this, we have engineered a novel device to generate such temperature gradients for in vitro or greenhouse experiments. Most of the experiments designed to study plant adaption to heat stress apply homogeneous high temperatures to both shoot and root. However, this treatment does not mimic the conditions in natural fields where roots grow in a dark and in a temperature descendent-gradient environment. Excessively high temperatures severely reduce cell division in the root meristem, compromising root growth, while increasing cell division of quiescent center cells, likely in an attempt to maintain the stem cell niche in such harsh conditions. Here, we engineered the TGRooZ, a device that generates a temperature gradient for in vitro or greenhouse growth assays. The root system of plants exposed to high temperatures in the shoot, but cultivated in the TGRooZ, grows efficiently and maintains its functionality to sustain proper shoot growth and development. Furthermore, gene expression and rhizosphere or root microbiome composition of TGRooZ-grown roots is significantly less affected than high temperature-grown roots, correlating with a higher root functionality. Our data indicate that by using TGRooZ in heat stress studies, we can improve our knowledge of the plant response to high temperatures and the applicability of laboratory studies to the field.